Raikou, The Thunder Pokémon. The RainClouds it carries let it fire Thunder Bolts at will. They say it descended with the Lightning. It races around the land barking it's cry that sounds like Crashing thunder. It stores energy in it's body and while running across the land it shoots off the excess electricity. It embodies the speed of Lightning. It's roars send Shockwaves through the air which shake the ground as if a thunderbolt hit.

Battle Moveset

A Good Moveset for Raikou would have to be this:

Attacks:

Thunder Bolt
Calm Mind
Crunch
Hidden Power Grass

Items Attached:

Salac Berry

Preferred Nature:

Modest

Strategy Using Raikou

HP Grass can be replaced with Reflect if you wish to have that extra defense to last in battle. This is also the only decent move it can learn in terms of increasing its defenses.
The moveset is simple, Calm mind to increase the strength of Raikou's special attack and special defense. Sweep with Thunderbolt, crunch and HP Grass. HP Grass will cover its ground/rock weakness. Crunch is simply a good dark type move which has the chance of lowering your opponent's special defense.
Thunderbolt gains strength from STAB and is also an excellent sweeping move.
Salac berry will increase Raikou's speed when its HP gets low, which will help Raikou out in situations where he needs the speed boost against faster pokemon than itself(like Dugtrio for example)
The nature ups Raikou's special attack while reducing its attack, which is beneficial for this pokemon since its no good as a physical sweeper.
The EV's are intended to give Raikou the edge while attacking with its special moves and being able to withstand some physical attacks. Originally I was planning to give Raikou a moveset like this: Rain dance, Thunder, Crunch, HP Grass for obvious reasons, but since Rain dance/Thunder has become quite common on Electric pokemon, I decided against it.

EV Corner:

Max out the EVs in Special Attack for Raikou with any remaining in Defense & HP

Strategy Against Raikou

Raikou is a Legendary and therefore has good defenses...however its Physical Defense is only just above average so if you attack with Physical attacks and Ground attacks...it'll be down in no time

Contest Moveset

A good Contest Moveset for Raikou would have to be this for the Cool Contest best with Lonely, Adament, Naughty or Brave Nature:

Attacks:

Rain Dance
Thunder
Thunderbolt
Hyper Beam

Items Attached:

Red Scarf

Strategy Using Raikou

If you do the attacks in this following order you should have very few problems; 1st - Rain dance, 2nd - Thunder/Thunderbolt, 3rd - Rain Dance, 4th - Thunder/Thunderbolt, 5th - Hyper beam

Locations in Games

Ruby/Sapphire

Trade from C/FR/LG

Colosseum

Shadow Research Lab, Realgam Tower, Deep Colosseum

Fire Red/Leaf Green

The Grasses All around Kanto if you picked Squirtle as your Starter

Animé Appearences

Raikou has had thee Animé Appearences. First, Togepi & Houndoom spotted it while Houndoom was taking it back to Misty. After that, one was spotted by New Bark Town by Yoshi & Dani. It was being attacked by Team Rocket and it was up to Yoshi, Dani, Jackson & Eusine to stop the Team Rocket members from taking this Raikou